Failed to remove the shaft coupling

Lucas Gan

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5 Oct 2018
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Done one and a half hole on the 20mm thick steel plate now by used one battery. Need to recharge it, which mean need 4 charges to make the job done. Should be able to try it on boat tomorrow.
 

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OBB

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If the removed screws were Allen screws were there perhaps another pair under the first pair?
Or
Is it a tapered key?
 

Croftie

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Done one and a half hole on the 20mm thick steel plate now by used one battery. Need to recharge it, which mean need 4 charges to make the job done. Should be able to try it on boat tomorrow.
Your not trying to do a 10mm hole in one go are you?
3mm hole then enlarge to 6mm them 8mm then 10mm
 

RAI

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That key and key way looks suspicious to me. One or the other could be tapered, either to jam the flange on, or to release it.
I would be tempted to get a drift and hammer to it.
 

Lucas Gan

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@OBB I can confirm there is no more screw. And it is not tapered as the end of the shaft is exactly 45mm in diameter.

@Croftie I did stupidity drill 10mm in one go! Not too bad, nearly done now.

@penfold Haven't go to the yard. Just do it at home.

@RAI The key may be useful when reattaching the coupling. But can't remove it in this case.
 

Lucas Gan

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10mm drill holes are too tight for M10 bolts when the steel plate is attached to the coupling. Maybe because the holes have a bit angle while drilling. Need to buy a 12mm drill bit to make it bigger and try again.
 

Lucas Gan

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Unfortunately, it's not coming off. Not even a little movement after 24 hours holding the steel plate with 6 bolts tighten to maximum and heated many times to untouchable hot. I am stuck!

I will just let it continues holding. I am trying to free up the stuffing box to keep using it. The problem is the stuffing box nut also won't move! Frustrating!
 

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fisherman

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Remarkable! Does your spacer cover the end of the key? If the keyway is closed then that would prevent movement.
 

TheCoach

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Remarkable! Does your spacer cover the end of the key? If the keyway is closed then that would prevent movement.
Good question, from the original photo it looks like the keyway protrudes quite a long way into the shaft so just check the spacer isn't fouling this.

I know its been asked before and you have checked already but have you been able to eyeball down the grub screw shaft to check there isn't a second grub screw? Another way to check would be to use the depth gauge on you caliper to measure down the grub screw hole and check this depth is the same as the flange thickness

Only reason I suggest this is some of the Mills and lathes I have used use an outer grub screw to protect/lock in an inner one.

Keep smiling ;)

Cheers

TC
 
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